Thermal fly-height control (TFC,) is known in the art, in which a fly-height-adjustment heating element is disposed in a head-slider so that a write element is displaced towards a magnetic-recording disk side by thermal expansion. Engineers and scientists engaged in HDD manufacturing and development are interested in the design of HDDs that control the fly height and variations in the fly height between the write element of the head-slider and the magnetic-recording disk to meet the rising demands of the marketplace for increased data-storage capacity, performance, and reliability.